In a pathname expansion, specifically single-character match, the pure
POSIX specification uses '!' as the Negation character where a regular
expression would normally be '^'.
Regular expression: "a[^a]a"
Pathname expansion pattern: "a[!a]a"
Reference:
IEEE Std 1003.1, 2004 Edition
2. Shell Command Language
2.13 Pattern Matching Notation
2.13.1 Patterns Matching a Single Character
> The description of basic regular expression bracket expressions in the
> Base Definitions volume of IEEE Std 1003.1-2001, Section 9.3.5, RE
> Bracket Expression shall also apply to the pattern bracket expression,
> except that the exclamation mark character ( '!' ) shall replace the
> circumflex character ( '^' ) in its role in a "non-matching list" in
> the regular expression notation. A bracket expression starting with an
> unquoted circumflex character produces unspecified results.
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
f6c3896087